EA008823B1 - IMPROVED DISTRIBUTION PROFILE OF SPEED SPEEDS OF THE RUNNING WHEEL - Google Patents

Abstract

In accordance with the present invention, the impeller for a centrifugal pump contains at least one blade, the radially outer end part of which is shaped to create a flow velocity distribution profile that controls and reduces wear caused by a fluid suspension displaced from the impeller onto the inner surface of the pump housing. In the configuration of the impeller blades according to the present invention, in most cases an outwardly projecting portion is made, in contrast to the traditional straight or concave edge of the impeller blade. The shape of this outwardly extending portion may vary, but it is selected so as to create a flow velocity distribution profile that reduces wear on the pump housing.

Description

The present invention relates to impellers of pumps, and, in particular, relates to an impeller having blades of a configuration specified in a particular way to selectively establish the profile of the distribution of speeds of the impeller, so as to selectively reduce the wear of the pump housing during the processing of suspensions.

Dynamic centrifugal pumps are used in a wide range of industries for the processing of liquids and suspensions. The type of fluid undergoing treatment dictates the type and configuration of the pump that is used in the particular application. That is, when pumping clear liquids, there are fewer requirements for pumps than when processing slurries that are; contain a certain amount of solid phase or solid particles, which are abrasive and destroy the internal structures of the pump.

Therefore, pump designers and engineers should take into account the type of fluid or slurry to be processed and select or design an impeller and pump housing most suitable for this application. For example, it is characteristic of the process of processing transparent liquids (for example, water) that the pump casing has the shape of a cochlea, the outlines of which vary in the cross-sectional area from the cutwater of the pump almost to the outlet of the pump, and relatively little water can be found in the pump casing.

However, in the process of processing suspensions, pump designers must take into account the impact of the hydraulic geometry of the surface, not only from the point of view of optimizing pump performance, but also from the point of minimizing wear in the pump housing. Thus, when designing pumps for suspensions, it was typical to modify the usual cochlear form of pumps for processing transparent liquids in order to provide, for example, wider outlets from the impeller, and cases with parallel sides.

Another factor determining the wear of the pump casing is the shape of the impeller blades. In particular, a significant effect of the outer edge of the impeller blades on the flow rate of the fluid moving through the pump was demonstrated. It has been observed that a typical blade configuration, having a straight outer edge on or near the outer edge of the casing, produces a certain fluid velocity, which leads to wear of the pump body along the walls of the volute in the shape of a cochlea.

The objective of the invention is to create an impeller having blades, which are designed in a special way, or the shape of which is made so that the wear pattern becomes more uniform, thereby extending the overall service life of the pump housing to the extreme wear in the production of suspensions, especially those that have high the solids content and / or, in the first place, the high abrasive solids content.

The problem is solved by means of an impeller having at least one blade, which is shaped in a special way on its outer end region, in order to create flow rates that are less destructive with regard to the wear of the pump casing when processing suspensions. Blade configurations according to the present invention are easily adaptable for use in any dynamic pump that uses an impeller, but here they are described and illustrated in connection with the application in a centrifugal pump for suspensions.

The impeller according to the present invention contains at least one blade, which protrudes from the center point of the impeller or near it in the direction corresponding to the center axis of the pump, and extends in the radial direction up to the outer edge of the impeller, where the blade has an outer end portion given forms. The impeller of the present invention may comprise a single casing (commonly known as a semi-open impeller), two enclosures (commonly known as a closed impeller) or may not contain a casing (commonly known as an open impeller). However, in the invention described herein, it has at least one casing oriented towards the working side of the pump casing (i.e., opposite the pump inlet).

In the configuration of the outer end portion of the blades according to the present invention, there is provided a portion protruding in the radial direction upwards, which, as a rule, outlines the convex edge of the blade. The term “convex” as used here is not limited to the traditional definition of a curved surface, but is intended only to indicate that the external end edge of the blade extends radially upwards relative to the central axis of the impeller, and is not straight or curved in the radially downward direction. towards the central axis of the impeller; however, the outer end edge may be made in any shape, including, but not limited to, hemispherical, curvilinear, or consisting of two or more intersecting straight lines.

The outer end portion of the blades, which has the shape of a bulge in accordance with the present invention, creates, as a rule, a velocity distribution profile for the fluid, which reduces wear on the inner surface of the pump casing. The shape of the convex outer end of the blades can be chosen in a special way to more carefully modify or define the distribution profile

- 1 008823 speeds of the fluid so that, given a particular type of suspension to be processed, the wear of the pump body can be kept under control and reduced.

The present invention is illustrated by the drawings, in which FIG. 1 is a vertical projection of a centrifugal pump, representing a typical centrifugal pump housing in a spiral chamber;

FIG. 2 is a cross section of the pump along line 2-2 in FIG. one;

FIG. 3 is a partial section in cross section of a traditional impeller blade, representing the end portion of the blade, made in the form of a straight edge;

FIG. 4 is a partial section in cross section of another conventional impeller blade, representing the end portion of the blade, made in a concave shape;

FIG. 5 shows a velocity distribution profile for a blade having an end portion, as shown in FIG. 3, schematically;

FIG. 6 shows a velocity distribution profile for a blade having an end portion, as shown in FIG. 4 schematically;

FIG. 7 shows a velocity distribution profile for a blade with a configuration according to the present invention, the end of which has an outwardly protruding edge;

FIG. 8 is a cross section of a first preferred embodiment of the present invention;

FIG. 9 is a cross section of a second preferred embodiment of the present invention;

FIG. 10 is a cross section of a third preferred embodiment of the present invention;

FIG. 11 is a cross section of a fourth preferred embodiment of the present invention;

FIG. 12 is a cross-sectional view of the fifth and sixth preferred embodiments of the present invention;

FIG. 13 is a cross section of a sixth preferred embodiment of the present invention;

FIG. 14 is a cross-section of a seventh preferred embodiment of the present invention.

FIG. 1 shows a conventional centrifugal pump 10 comprising an impeller 12 and a pump casing 14. The inlet 16 is formed through the pump casing 14, which delivers the incoming fluid to the impeller 12. The pump casing 14 shown in FIG. 1, is a spiral-shaped body in the form of a cochlea, which extends from the cutwater 18 to the outlet 20. As shown by the arrows located inside the pump-body 14 in FIG. 1, and is further represented in cross section of FIG. 2, that the cross-sectional area of the spiral chamber of the pump typically increases from the cutwater 18 of the pump 10 to the outlet 20 of the pump 10.

As shown in FIG. 2, as the impeller 12 rotates the drive shaft 22, the fluid entering the inlet 16 moves into the impeller 12 and is forced out into the spiral chamber 24 of the pump casing 14. The displaced fluid further moves through the spiral chamber 24 of the pump casing 14 from the cutwater 18 to the outlet 20, flowing in the area of the pump casing 14 with a constantly increasing cross-sectional area, as shown in FIG. 2

As shown in FIG. 1, the impeller 12 of a conventional pump comprises at least one blade 30, and, as a rule, a plurality of blades 30 that extend out from or near the point 32 in the center 32 of the impeller 12. As shown more clearly in FIG. 3, for example, the impeller 12 may have a casing 34, which, as a rule, is made in the form of a flattened disc having a central point 32 corresponding to the central axis of the pump. The blades 30 protrude outward from a point located in or near the center 32 of the casing 34 towards the outer edge 36 of the casing 34, where the blades 30 end. Each blade 30 has a leading plane 38, which the incoming fluid encounters as this fluid is pushed radially outward to the spiral chamber 24 of the pump housing 14 (Fig. 2).

As shown in FIG. 3, the outer end portion 40 of each blade 30 is bounded by an edge 42, as shown in the cross section, along the line through the blade 30. FIG. 3 shows the first conventional configuration for a blade 30, which has a straight edge on the outer end portion 40 of the blade 30. As shown, the straight outer edge 42 of this conventional type of blade 30 coincides, as a rule, with the outer edge 36 of the casing 34.

On. FIG. 4 shows another conventional configuration of the impeller 30, where the outer edge 44 of the outer end portion 40 of the blade 30 is concave, as shown in the cross section along the line X through the blade 30. That is, the outer edge 44 bends inward toward the center point 32 of the case 34, and 46 of the outer edge 44, does not coincide with the outer edge 36 of the casing 34.

The shape of the tip of the blade affects the flow rate of the fluid emanating from the impeller, and thereby affects the type or profile of wear that may be

- 2 008823 hundred in the pump housing during the processing of suspensions. As shown in FIG. 5, for example, a conventional blade having a straight outer edge 42 creates a larger velocity distribution profile of the fluid where the fluid is displaced at greater speed along the axial sides of the blade 48, 50, or near them than where it is displaced from the center of the blade between axial sides 48, 50. Consequently, the wear in the pump housing takes place on both sides of the spiral chamber in a spiral system.

As shown in FIG. 6, the flow velocity distribution profile created by a conventional vane having a concave outer edge 44 is similar to the propagation profile of the flow velocities created by the vane having a straight outer edge 42, except that a double peak takes place on the axial end portions of the vane flow rates. Therefore, in the process of pumping suspensions in the spiral chamber of the pump casing, a double spiral-shaped wear profile is observed. In both conventional blade configurations shown in FIG. 5 and 6, in the center of the spiral chamber of the pump, there is relatively little wear.

Considering the above, it is preferable to make a blade with such a configuration where the outer end portion has a shape suitable for forming a profile of the distribution of flow rates so as to provide more controlled and reduced wear in the spiral casing of the pump casing compared to the known traditional impeller blades. The inventors have discovered that a blade 60, having mainly a convex outer edge 62, as shown, for example, in FIG. 7 forms such a distribution profile of flow rates in which the speeds are distributed more evenly along the spiral chamber of the pump casing, and thus cause more uniform wear of the inner surface of the casing than under normal conditions with traditional configurations of blades.

FIG. 8 shows that, in general, the impeller blade 60 according to the present invention has an outer end portion 64 defining a convexly-shaped outer end edge 62, the outer edge 62 having a radially outwardly extending portion 66 that is located behind the outer edge 36 of the case 34. Thus, the radius _{ν of the} protruding portion 66, measured from the center 32 of the impeller 34 to the end point 68 of the blade 60, is larger than the radius K _{3 of the} casing 34. As explained in more detail below, the shape of the protruding portion 66, end portion 64 may vary, and may be specifically selected to provide the desired flow velocity distribution profile, provided that the requirements for pump operation in a given embodiment are met.

FIG. 8 shows the first preferred embodiment of the present invention, where the outer end portion 64 of the blade 60 has an outwardly protruding portion 66 with a radius _{ν ν} that is larger than the radius K _{3 of the} case 34. The outer edge 62 of the blade 60 is also assembled with portions 70, 72 with each the sides of the protruding portion 66, having a radius K ₃ , which in the present embodiment is equal to the radius K _{3 of the} casing 34. Thus, the blade 60 has a width ν _ν and the protruding portion 66 has a width ν _Ρ that is smaller than the width ν _ν shoulder blades 60. Follow t notice that other equally applicable to embodiments of the present invention described in more detail below, the width ν _Ρ outwardly projecting portion 66 may be equal to the width \ _ν ν blade 60.

In the first preferred embodiment of the present invention shown in FIG. 8, the outwardly protruding portion 66 in the segment from point A to the endpoint 68 of the outwardly projecting portion 66, and then to point B, has mainly the shape of an arc. Thus, by way of example only, the outwardly projecting portion 66 may have a radius K _s . However, the arcuate line between point A, end point 68 and point B does not need to have a constant radius (i.e., be a regular arc). It is obvious to those skilled in the art that the dimensions of the arcuate or curved line forming the outwardly projecting portion 66 can be appropriately changed to provide the desired profile for the distribution of flow rates, as already described here. In another preferred embodiment of the present invention shown in FIG. 9, the outer edge 62 of the blade 60 includes an outwardly protruding portion 66, the end point 68 of which limits the radius Κ _{ν of the} blade 60. In addition, on each side of the outwardly extending portion 66, the outer edge 62 has a portion 70, 72, the radius K3 _of which is less than radius K _{3 of} case 34. Further, radius K _{3 of} case 34 is smaller than the radius of the outwardly projecting portion 66. Outwardly protruding portion 66 is bounded between point A, end point 68 of the blade 60 and point B, and has a width ν _Ρ . This width ν _{Ρ of the} protruding portion 66 is smaller than the width ν _{ν of the} blade 60.

In another preferred embodiment shown in FIG. 9, is shown, by way of example only, a portion 66 protruding outwardly formed by two intersecting lines, the first line 74 being located between point A and the end point 68 of the blade 60, and the second line 76 being located between end point 68 and point B. This embodiment demonstrates that the shape of the protruding portion 66 may be not only an arcuate or curved line, as shown in FIG. 8, but can also be formed by a large number of intersecting lines. It is obvious to a person skilled in the art that the shape of the outer edge 62 of the blade can be suitably measured

- 3 008823 in a variety of different ways to provide the desired profile for the distribution of flow rates.

In the presented embodiments of the impeller blade in accordance with the present invention, the end point 68 of the blade 60 is shown, the center of which is located on the same axis with the center of width \ ν _{ν of the} blade 60. However, it should be noted that the end point 68 can be located differently than on the center line 80 of the blade 60 and width XV _ν . and depending on the prescriptions or requirements that must be followed to ensure the desired flow velocity distribution profile.

FIG. 8 and 9, embodiments of the invention are shown where the radius U of the blades represented on the representative cross-section view of the fifth preferred embodiment of the present invention is larger than the radius of the casing K ₃ and / or the base radius K _in .

Another preferred embodiment is shown in FIG. 11, where the radius U of the blades 60 and the radius K _{3 of the} casing 34 are mainly the same, and each of these radii is larger than the base radius K _{in the} blades 60. Each of FIG. 10 and 11 embodiments of the invention allows to obtain the desired profile of the distribution of flow rates and creates less wear on the spiral chamber of the pump casing. It should be borne in mind that represented in FIG. 10 and 11, the outwardly protruding portion 66 is shown as a hemisphere as an example only, and other convex shapes or dimensions of this portion can be attached and / or applied.

As noted above, the positions of point A and point B, which limit the axially opposite ends of the protruding portion 66, can be located anywhere from the zone near the middle line 80 (Fig. 8 and 9) of the blade 60 to the end in the axial direction of the parts 82, 84 of the blade 60, as shown in FIG. 12. Consequently, the distance ϋ between point A and point B can vary from Ο = \ ν _ν to approximately O = XY \ 73. and point a and point b can be located at equal, and not at equal distance from the middle line of the blade 60.

FIG. 12 shows that axially opposite ends of the outwardly projecting portion 66, bounded by point A and point B, extend to axially end portions 82, 84 of the blade 60. Essentially, shown in FIG. 12, the embodiment has no side portions (70, 71), as in the embodiments according to FIG. 8-11, but axially opposite ends (point A, point B) of the protruding portion 66 limit the radius K _{in the} blades 60. Thus, in the fifth preferred embodiment of the present invention shown in FIG. 12, the radius U of the blade 60, limited from the central axis 32 of the impeller to the end point 68 of the blade 60, is larger than the radius K _{3 of the} case 34, and the base radius K _in is equal to the radius of the case K ₃ .

In the sixth preferred embodiment, also shown in FIG. 12 with a dotted line, the cover 34 can extend beyond the base radius K _{in the} blades 60 by a predetermined distance, so that the outer edge 36 ′ of the impeller protrudes up to radius K ₃ ′. The radius Κ _{ν of the} blade 60, thus, is larger than the radii K _in and K ₃ '.

In the seventh preferred embodiment shown in FIG. 13, the end point 68 of the blade 60 may not reach the outer edge 36 of the case 34. Therefore, in this embodiment, the outwardly protruding portion 66 of the blade 60 does not extend beyond the case 34, but it still has a favorable effect on the velocity distribution profile of the impeller. In the embodiment shown in FIG. 13, the radius U of the blade 60 is larger than the base radius K _in , but smaller than the radius K _{3 of the} casing 34.

In another preferred embodiment of the present invention shown in FIG. 14, the end point 68 of the blade 60 protrudes to a point corresponding mainly to the outer edge 36 of the case 34 so that the radius U of the blade 60 and radius K _{3 of the} case 34 are substantially equal to each other, and the base radius K _is less than radius Κ _ν blades or radius K ₃ casing. In addition, despite the fact that the convex edge in the embodiments shown in FIG. 12-14, is an arcuate line, the outwardly projecting portion 66 may have any suitable shape, as already described above.

Regardless of how the shape of the protruding portion 66 of the shoulder blade 60 is shown and described above, the area of this shape preferably takes from 30% to about 85% of the area bounded by \ ν _ν (Εν-Κ _Β ). The table below shows, solely as an example, some of the possible range of aspect ratios, but they should not be understood as an exhaustive limitation of this range.

Minimum Maximum Preferred s Κν 1.02 K _in 1.15kv 1.06Kv Urluu 0.2 I 0.65 Kv K _a 1.15K _a 1.05K _in

The impeller blades of the present invention are configured to provide a predetermined velocity distribution profile that controls and / or reduces wear in the pump housing caused by a fluid suspension suspended from the impeller to the casing. shoulder blades

-4008823 impellers can be adapted for use in dynamic centrifugal pumps of almost any type, size or variety. Changes and reworkings that can be made to use the impeller blades in various pumps to obtain the desired velocity distribution profile are clear to the specialist. Therefore, the references here given to the specific details of the embodiments of the present invention are made solely as examples, and not as a limitation.

Claims (21)

1. The impeller for a centrifugal pump containing at least one blade protruding along the length in the radial direction from the Central axis of the impeller to the outer outer edge of the impeller, and having a middle line protruding along the radial length, which is perpendicular to the Central the axis of said impeller, and said at least one blade has an outer end portion located on or adjacent to the outer edge of said impeller, when om said outer end portion includes a projecting portion outwardly convex shape. 2. The impeller according to claim 1, which contains at least one casing having an outer edge defined by said outer edge of said impeller, said at least one blade protruding outward relative to said casing. 3. The impeller according to claim 2, in which the protruding portion has an end point and a radius Ku measured from said central axis of said impeller to said end point, said casing having a radius K ₃ measured from said central axis to said an outer edge, the radius being equal to or greater than the radius K ₃ . 4. Impeller according to claim 3, wherein the outer end portion of said at least one blade also includes a portion with _a radius R, the radius R is less than or equal _to radius R _3. 5. The impeller according to claim 4, in which the protruding outward portion has an arcuate shape. 6. The impeller according to claim 4, in which the protruding outward section has an outer edge formed by the intersection of at least two lines. 7. The impeller according to claim 4, in which at least one blade has a width of ν _ν , and the protruding portion of the outside has a width of ν _Ρ , while the width of ν _{Ρ is} less than or equal to the width of ν _ν . 8. The impeller according to claim 7, in which the area of the protruding outward portion is from 30 to about 85% of the area bounded by \ ν _ν (Ρ _ν -Ρ _Β ). 9. The impeller according to claim 1, in which the protruding outward section has an outer edge of a curve or an arcuate shape. 10. The impeller according to claim 1, in which the protruding outward portion has an outer edge formed by the intersection of at least two lines. 11. The impeller for a dynamic centrifugal pump, comprising a casing having a central axis and an outer edge located in the radial direction at a distance from said central axis, said casing having a radius of K ₃ ; and at least one blade extending axially outward from said casing and extending radially from the center of said central axis, or from a certain distance from it, to said outer edge, defining a midline of said at least one blade, which is located perpendicular to said central axis; wherein said blade is attached to said casing along the radial extension of said blade along said casing, and has an outer end portion located on or adjacent to said outer edge; wherein said outer end portion comprises an outwardly extending portion with a radius K _y measured from said central axis to the end point of said outwardly extending portion; and the radius is equal to or greater than the radius K ₃ . 12. The impeller according to claim 11, also containing a second casing located parallel to the casing and at a distance from it, wherein said at least one blade is located between the casing located at some distance from each other. 13. The impeller according to claim 11, in which the outer end part of said at least one blade also comprises a portion with a radius of K _in , while K _in is equal to the radius of K ₃ . 14. The impeller according to claim 11, in which the outer end part of the said at least one blade also contains a section with a radius of K _in , with K _in less than the radius K ₃ . 15. The impeller according to claim 11, in which the protruding outward portion has a convex shape. 16. The impeller according to claim 11, in which the protruding outward portion has a curved outer edge. 17. The impeller according to claim 11, in which the protruding outward portion has an outer edge formed by at least two intersecting lines. - 5 008823 18. The impeller according to claim 11, in which at least one blade has a width Au, and the shape area of the protruding outward portion is from 30 to essentially 85% of the area bounded by Α _ν (( _ν -Κ _Κ ). 19. Impeller on and. 13, in which at least one blade has a width Au, and the shape area of the protruding outward portion is 30 to substantially 85% of the area bounded by Α _ν (Κ _ν -Κ _Β ). 20. Impeller on and. 19, wherein the outwardly extending portion has an outer edge so shaped as to form a predetermined flow velocity distribution profile in order to reduce wear in the pump housing. 21. The impeller according to claim 2, in which at least one casing has a radius K ₃ measured from the central axis to the outer edge, and the protruding portion has an end point and radius Ku measured from the central axis of said impeller to said end points, and the outwardly extending portion has axially opposite ends defining a radius K _in measured from said at least one axial end to said central axis, wherein the radius K _is smaller than the radius Κ _ν , and the radii K ₃ and Κ _{ν are} smaller a radius of K ₃ . FIG. 2 -6008823 FIG. 6 FIG. 8 -8008823 during FIG. nine FIG. 10 FIG. eleven